arXiv subjects
Publications and source records attributed to Leonid Gladilin.
Recent results of the ATLAS experiment at LHC on hadron spectroscopy, including exotic states, are presented. Comparison of the results with various theoretical predictions is discussed.
The fragmentation fractions of c and b quarks into the weakly decaying charmed hadrons D0, D+, D_s+ and Lambda_c+, and into the charmed vector meson D*+ have been derived from the LEP measurements and averaged. The c quark fragmentation fractions represent probabilities to hadronise as a given charmed hadron, while the b quark fragmentation fractions are defined as sums of probabilities to hadronise as a particular charmed hadron or its antiparticle.
Various strange and charmed hadrons were reconstructed with the ATLAS detector in pp collisions at sqrt{s}=7 TeV. The data sample was collected in March-May of 2010 using a minimum-bias trigger. The K^0_S and Lambda^0 kinematic distributions were studied using data corresponding to an integrated luminosity of 190 mub^{-1}. The Xi-+ and Omega-+ baryons were reconstructed in their cascade decays in data corresponding to an integrated luminosity of 250 mub^{-1}. The D*+-, D+- and D_s+- charmed mesons were reconstructed in the range of transverse momentum pT(D^(*))>3.5 GeV and pseudorapidity |eta(D^(*))|<2.1 in data corresponding to an integrated luminosity of 1.4 nb^{-1}. The fitted mass values were found to be in agreement with their world averages while the observed invariant mass resolutions agree with Monte Carlo expectations. This study confirms the high performance of the ATLAS detector for precision tracking measurements.
The talks presented in the working group ``Heavy flavours'' of the DIS-2009 workshop are summarised. New and recently updated results from theory, proton antiproton and heavy ion colliders, as well from HERA and $e^+e^-$ colliders are discussed.
The charm fragmentation function has been measured in photoproduction of jets containing D^*+- mesons. The measured function has been used to extract free parameters of different fragmentation models. Measurements of excited charm, D_1(2420)^0 and D_2^*(2460)^0, and charm-strange, D_{s1}(2536)^+-, mesons and a search for the radially excited charm meson, D^{*'}(2640)^+-, were also performed. The results are compared with those measured previously and with theoretical expectation.
Light and charmed hadrons are produced copiously in ep collisions with a centre-of-mass energy of 318 GeV at HERA. Results of the ZEUS Collaboration on pentaquark searches, deuteron and antideuteron production and charmed-meson spectroscopy, obtained using the HERA I data, are summarised.
Experimental results on c- and b-quark fragmentation are reviewed. The discussion is concentrated on measurements of heavy-quark fragmentation functions and fragmentation fractions. Measurements of various heavy-quark fragmentation ratios are also discussed. The experimental results are compared with theoretical expectations and model predictions.
Results of the H1 and ZEUS Collaborations on spectroscopy of light and charmed mesons and on pentaquark searches, obtained using the HERA I data, are summarised.
The experimental talks presented in the working group D ``Heavy Flavours'' of the DIS04 workshop are summarised. New and recently updated results from Tevatron, HERA, LEP, B-factories and neutrino experiments are discussed.
Dijet angular distributions of photoproduction events in which a D*+/- meson is produced in association with one of two energetic jets have been measured using an integrated luminosity of 120 pb^1. The results are compared with predictions from leading-order parton-shower Monte Carlo models and with next-to-leading-order QCD calculations.
The measured D*+/-, D0, D+/-, D_s+/- and /\_c+/- photoproduction cross sections have been used to determine charm fragmentation ratios and fractions of c quarks hadronising as a particular charm hadron, f(c -> D, /\_c). Events with a D*+/- meson produced in association with an energetic jet have been used to measure the charm fragmentation function. The results are compared with different models and with previous measurements.